Hydraulic press



Filed May 10, 1926 2 Sheets-Sheet 1 gwuznioz attozmqd Aprll 12, 1927. R. CRAIG HYDRAULIC PRESS Filed May 10, 1926 2, Sheets-Sheet 2 I Ill Patented Apr. 12, 1927.

UNITED STATES 301mm CRAIG, or DAYTON, 01110.

HYDRAULIC PRESS.

Application filed May 10, 1926. Serial No. 107,911.

This invention pertains to hydraulic presses, particularly of the k1nd suitable for use in machine shops, and garages, for pressing bushings into gears, straightening shafts, etc.

It has been customary to use screw presses 'for such work but screw operated machmes have many disadvantages. They are very inefficient, especially when not well lubricated, and they are very slow in operation due largely to the time required to run the screw down to, and up from, the work.

Hydraulic presses have been used 1n place of screw presses, but they also have had drawbacks. Either they were too slow 1n operation, or they required too much manipulation of valves and levers, or they lacked suitable means for raising the ram from the work, etc.

The principal object of the present invention is to provide a press which avoids the above shortcomings, is moderate in cost, s1m ple, easy to handle, and which lends itself to very rapid 0 eration.

It is an object of the invention to be able to lower the ram rapidly to the work.

Another object is to be able to shift instantly from high-speed low-pressure to slow-speed high-pressure conditions.

Another object is to provide means to raise the ram at very high speed, hydraulically, without the use of gears, springs, etc.

Another object is to provide a simple lever-controlled device which enables the operator to shift instantly from any operating condition to any other operating condition.

Another object is to provide means by which the ram may be used to help raise or lower the working table or bolster of the machine from one position to another.

Further and other objects and advantages will be hereinafter set forth in the accompanying specification and claims, and shown in the drawings, which by way of illustration show what is now considered to be the preferred embodiment of the invention.

Fig. 1 is a side view of the machine with a portion of the channel cut away.

Fig. 2 is a front view of the machine.

Fig. 3 is a view of the oil reservoir. and pump, and a sectional view of the hydraulic cylinder. I I

Fig. 4 is a plan view of the pump with valve control lever.

Fig. 5 is a diagrammatic view, mostly In section, showing setting of control valve for fast down operation.

Fig. 6shows position of control valve for slow down.

Fig. 7 shows fast up.

The frame of the machine comprises the vertical channels 10, across the tops of which are bolted or riveted the cross channels 12. Through the flanges of the Vertical channels are drilled holes 14, into which may be placed pins 16, on which rest the channels 18 forming the work table of the machine. Channels 18 are usually spaced apart by sleeves 20 on bolts 22, the sleeves being long enough to prevent the bolster from binding on the vertical channels when it is moved to a new position. Angles 24 are bolted to the lower ends of members 10 to provide feet for the machine.

Mounted between channels 12 at their middle, is the hydraulic cylinder 26, bolted to the lower surfaces of the channels by flange-28, which is integral with the cylinder. Between channels 12 and alongside cylinde 26 is supported an oil reservoir 30.

position of control valve for Mounted over an aperture in the floor of the reservoir is a pump 32 (Fig. 3). The pump is provided with a large plunger 34 and a small plunger 36. Suitable check valves are provided so that each plunger can pump independently of the other. Oil is generally used as the operating liquid, the pump being immersed in the oil.

Both plungers' 34 and 36 are pivotally connected to an overhead lever. 38, which is fulcrumed at 40 by means of, links 42. The free end of lever 38 is connected by vertical links 44 to hand lever 46, which is pivoted on the bracket 48 fast to the frame of the machine. When handle 46 is moved up and down, both pump plungers move up and down and both pump oil from the reservoir into various passages, depending on the 10- cation of the control valve 50, the operation no of which will be later explained. For convenience I have shown the pumps as hand operated, but they may be power operated if desired.

From pump 32, pipe 52 extends to the head, and pipe 54 to the lower. end of cylinder 26. Both pipes 52 and 54 serve as either supply or discharge pipes, as will ap ear.

ithin cylinder 26 is the plunger or ram 56, of somewhat smaller diameter than the bore of the cylinder. The upper end of ram 56 is provided with cup leathers 58 and 60, facing upwardly and downwardly respectively, while surrounding the ram near its lower end is the U packing 62. Packing 62 is held in place by flange 64 bolted to the lower side of flange 28 and having a passage 66 through it, to which ipe 54 is connected.

Bored horizontally t rough pump body 32 is a cylindrical valve chest 68. Into this chest enter pipes 52 and 54, also discharge passages 70 and 72 from the large and small pump plungers (Figs. 5, 6 and 7). In chest 68 is valve 50, slidable back and forth by means of stem 74 having a slotted head 76 which is engaged by arm 78 (Fig. 4) fast to a vertical rod 80. to which rod, at its upper end, is pinned the horizontal lever 82. Lever 82 may be set in any one of three notches in quadrant 84. to position valve 50 in an of its three positions. Valve 50 is provi ed with two piston-like portions 86 and 88. Pipes 52 and 54, passages '70 and 72, and pistons 86 and 88 are so located with reference to each other that various results are obtained with different settings of valve 50, as will be understood by reference to Fi s. 5, 6 and 7.

Feferring first to Fig. 5, and remembering that plungers 34 and 36 are always both operating, it will be seen that both plungers are discharging, through their passages 70 and 72, through that portion of chest 68 between pistons 86 and 88, into the upper end of cylinder 26, resulting in ram 56 being forced rapidly downward. Oil contained in the annular space 90 between ram 56 and cylinder 26 is forced through pipe 54 and the open end of cylinder 68 into tank 30 which surrounds the pump.

After the ram has reached the work, or if for any reason it is desired to apply greater pressure to the ram, at lower speed, lever 82 is moved to place valve 50 in the position shown in Fig. 6, in which position it will be noted that only the oil from the small plunger 36, through passage 72, is entering pipe 52 to pass into cylinder 26. Plunger 34 is discharging idly through the open end of chest 68, as is also pipe 54, as before. If plunger 34 has ten times the area of plunger 36, then when both plungers are discharging into cylinder26 the ram will move eleven times as fast as when only plunger 36 is discharging into the cylinder alone. but when plunger 36 is operating alone it will supply eleven times the pressure per unit of area, as the two plungers combined, assuming the power input the same in both cases. a

If now it be desired to raise the ram, control lever 82 is moved to place valve 50 in the position shown in Fig. 7, in which position it will be seen that the discharge from large plunger 34 is passing through passage 76, chest '68, and pipe 54, which leads to the annular space 90 below cup leather 60, raising the ram. At the same time, oil contained in the upper end of cylinder 26 is being discharged through pipe 52 and the open end of chest 68 into the tank. The discharge from small plunger 36 is also passing idly into the tank by way of pipe 72 and chest 68. As the cross sectional area of the annulus 90 is much less than that of cylinder 26 it is evident that the upward speed of the ram under the conditions in Fig. 7 is much higher even than the fast downward speed procured by the setting of Fig. 5.

The above description shows that my invention provides a fast down speed, a slow down speed, and a very fast up speed, by slight changes ofposition of a simple one-piece valve. A pressure gage 92 is provided for the convenience and guidance of the operator.

The bolster 18 is too heavy for a single operator to handle unaided when it must be moved from one position to another, so 1 make provision whereby the ram may be utilized to assist the operator in handling the bolster. Through each bolster channel 18, at the middle of its length, a hole 94 is provided. A hole 96 is drilled horizontally through the lower end of ram 56. When it is desired to move the bolster, a pin 98 is slipped through holes 94 and a pin or bolt 100 through hole 96 and the two pins are connected by a chain 102, all as indicated in Fig. 1. Raising of the ram lifts the bolster from pins 16, which may then be removed, the bolster raised or lowered, and finally placed on pins 16 in the new position.

It is to be understood that the invention is not limited to the specific construction herein illustrated and described but can be embodied in other forms without departure from its spirit.

lVhat I claim is:

1. In a hydraulic press, in combination, a cylinder, a plunger arranged for forward and back motion in said c'ylinder, a pump operable to discharge a uniform volume of liquid, and settable means comprising a single valve to regulate the flow of liquid from said pump to said cylinder to impart to said plunger either a slow or fast forward speed or a fast return speed.

2. In a hydraulic machine, in combination, a device arranged for action in two directions, a supply of oil under pressure, and means comprising a single valve settable to regulate the flow of oil to impart to said device either a slow or fast speed in one direction or a fast speed in the other direction.

3. In a hydraulic machine, in combination,

rections, a pump operable to supply oil to said device, and a single valve settable to regulate the flow of oil from said pump to operate said device either at slow or high speed in'one direction or still higher speed in the other. direction.

4. In a hydraulic machine, in combination,

a device arranged for operation in two directions, a valve chest, a valve in said valve chest, a pump operable to supply oil under pressure to said chest, and passages connecting said chest to said device; said "alve being settable to control the flow of oil from said chest through said passages to impart to said device either a slow or high speed in one direction or a high speed in the other direction.

5. In a hydraulic machine, in combination, a pump arranged to discharge a stream of oil, a device operable in either of two directions by said oil and means comprising a single valve settable to regulate the flow of said stream of oil to operate said device at either a slow or a high speed in one direction or a high speed in the other direction.

6. In a hydraulic machine, in combination, a valve chest, a pump arranged to supply two streams of oil to said chest, a device operable in two directions, waste outlets from said chest, a plurality of outlets from said chest to said device, and a valve settable in said chest to so distribute said streams of oil among said'chest outlets as to operate said device at either a slow or a high speed in one direction or a high speed in the other direction.

7. In a hydraulic machine, in combination, a valve chest, a pump arranged to discharge a large and a small stream of oil into said chest simultaneously, a device operable in either of two directions, and a valve settable in said chest, to cause said device to be opera-ted in one direction either by the small stream of oil alone or by both streams together, or in the other direction by the large stream alone.

8. A hydraulic device comprising in combination, a valve chest, two inlets to said chest, means to supply oil through said inlets, two discharge outlets from said chest, and a valve settable to three positions in said chest, in the first of which positions the oil from both inlets discharges into one outlet, in the second position of which the oil from only one inlet discharges into the one outlet, and in the third position of which the oil from one inlet discharges into the other of said outlets.

9. In a hydraulic press, in combination, a cylinder closed at one end and open at the other end, a plunger in said cylinder and projecting from the open end thereof, a pump, a valve chest and a valve in said chest, said valve being settable to so control the flow of oil from said pump to said cylinder as to impart to said plunger a slow or a fast speed outwardly from said cylinder or a fast speed inwardly thereto.

10. In a hydraulic press, in combination, a cylinder closed at its upper end and open at its lower end, a plunger in said cylinder projecting from the lower end thereof, packing on the upper end of said plunger, pack ing around said plunger near the open end of said cylinder, a pump operable to discharge two streams of oil, a valve chest, and a valve in said valve chest, said valve being settable to so control the flow of the streams of oil from said pump as to direct either one or both streams into the upper end of said cylinder or one stream into the lower end of said cylinder around said plunger and above said lower packing, for the purpose set forth.

11. A hydraulic press comprising in combination, two oil pumps, means to apply power to operate said pumps simultaneously, a cylinder, a plunger adapted for up and down motion in said cylinder, a tank for oil, a valve chest, passages from both of said pumps to said chest, passages from both ends of said cylinder to said chest, a passage from said chest to said tank, and a valve settable in said valve chest to so control the flow of oil from said pumps through said passages as to impart either a slow or fast downward motion or a fast upward motion to said lunger. I 12. A hydraulic press comprising in com bination, a valve chest, two oil pumps arranged to discharge oil into said valve chest, means to operate said pumps simultaneously, passages'to conduct the oil discharged from both said pumps to said valve 'chest, a vertical cylinder, a plunger adapted for up and down motion in said cylinder, pipes leading from said chest to both ends of said cylinder, waste outlets from said chest, and a valve settable in said chest to so control the flow of oil from said chest through said waste outlets and said cylinder pipes as to impart either a slow or fast" downward motion or a fast upward motion to said plunger.

13. In a hydraulic press, in combination, a'cylinder, a plunger arranged for up and down motion in said cylinder, a valve chest, a pump operable todischarge oil into said chest, means to apply power to said pump, passages for oil from said chest to said cylinder, and a valve settable in said chest to so control the flow of oil from said pump to said cylinder as to impart to said plunger without change of applied power, either a high speed low pressure downward motion, a slow speed high pressure downward motion, or a high speed low pressure upward motion. p

14. In a hydraulic press, in combination, two pumps, means for operating said pumps in unison, a valve chest, a first outlet from said chest, a second outlet from said chest, a discharge passage connecting each of said pumps to said chest, and a valve settable in said chest to direct the discharge from both of said pumps into said first outlet, or from one of said pumps alone into said first outlet, or from the other of said pumps alone into said second outlet.

15. In a hydraulic press, in combination, a large oil pump, a small oil pump, means for operating said pumps in unison, a valve chest, a cylinder having upper and lower ends, a discharge passage from each of said pumps to said chest, pipes for oil from said chest to said upper and lower cylinder ends respectively, Waste outlets from said chest, and a valve settable in said chest whereby the upper end of said cylinder is filled by the oil from both of said pumps, or fronr said small pump while said large pump discharges through one of said Waste outlets, or the lower end of said cylinder is filled by oil from said large pump while said small pump discharges through one of said Waste outlets, the contents of either end of said cylinder being discharged through its connecting pipe and said waste outlets while the other end of said cylinder is being filled, for the purpose described.

16. In a press, in combination, a vertical plunger, means to supply power to said plunger to move it up and down, a work table, means for supporting said table in various positions relatively to said plunger, and devices connecting said table and said plunger whereby the motion of said plunger may be utilized to move said table from one of said positions to another.

17 In a press, in combination, a plunger, means for actuating said plunger, a bolster, means for supporting said bolster in various positions, and devices connecting said bolster to said plunger actuating means for the purpose set forth.

18.'In a hydraulic press, in combination, a cylinder, :1 plunger in said cylinder, means to supply oil to said cylinder to actuate said plunger forward or back in said cylinder. a bolster, meansfor supporting said bolster in various operative positions relatively to said plunger, and supplen'ientary devices interconnecting said plunger and said bolster to permit actuation of said plunger to move said bolster from one to the other of said operative positions. 1

In testimony whereof I hereto afiix my signature.

ROBERT CRAIG. 

